The invention relates generally to telecommunications equipment, and more particularly to a personal videoconferencing system.
Businesses are making increasing use of videoconferencing systems to enable geographically remote individuals or groups to communicate with each other from their respective locations. By offering the ability to communicate graphic information and to view the facial expressions and gestures of the conference participant(s) located at a remote site, videoconferencing facilitates richer and more natural communication between conference participants when compared to traditional audio-only conferencing. Regular use of videoconferencing avoids or significantly reduces the need for expensive and time-consuming business travel.
Several commercial vendors are presently manufacturing and selling high-quality videoconferencing systems for business use. Such systems tend to be expensive to purchase and maintain, bulky in size, and difficult to configure and operate. Due to the expense and size of business videoconferencing systems, as well as the necessity to connect each system to multiple digital telephone lines, businesses desiring to utilize videoconferencing often purchase a relatively small number of videoconferencing systems for common use of the employees and install each system within a conference room or area, rather than in individual employee""s offices. Persons wishing to use a videoconferencing system must typically reserve the associated conference room in advance, and may need to secure the assistance of a system administrator or other IT professional to set up the video call to the remote conferencing site and to configure and operate the videoconferencing system prior to and during the conference. The need to arrange aspects of the videoconference in advance and to travel to the conference room in which the videoconferencing system is situated may dissuade certain persons from availing themselves of the benefits of videoconferencing.
A number of personal videoconferencing devices have been developed and are presently commercially available. These devices typically comprise low resolution video cameras connected to a desktop personal computer through a USB port or similar interface. Raw (unencoded) video generated by the video camera (representative of a user""s image), together with raw audio generated by a microphone (representative of the user""s speech) are sent to the desktop computer to be encoded prior to transmission of the encoded audio and video data to a remote site through a network interface or modem. The desktop computer also handles decoding of incoming audio and video data received from the remote site, as well as echo cancellation, media stream packetization and call establishment and control.
Because the audio/video encoding and decoding processes tend to be computationally expensive, most desktop computers are limited to low bit-rate videoconferencing. This limitation results in poor image quality and jerky motion (as well as poor speech reproduction), which may distract the user and substantially reduce the videoconferencing device""s effectiveness as a communication tool, particularly in a business setting. Video and audio quality may be improved by installing a video capture and processing board in the desktop computer, which handles various processing tasks associated with the audio and video streams. However, many persons, particularly those having limited technical sophistication, may be dissuaded from purchasing and using board-based systems because of the need to open up the desktop case and physically install the board in an appropriate slot on the motherboard. Further, board-based systems may require the user to perform non-trivial configuration of the associated desktop computer to ensure that the board is properly configured and hardware conflicts do not arise.
Thus, a need remains for a personal videoconferencing system which is compact, easy to set up and configure, and which provides business-quality audio and video.
In accordance with one aspect of the invention, a personal videoconferencing system includes a videoconferencing appliance connected to a personal computer (PC) via a Universal Serial Bus (USB) or comparable communication interface. Processing tasks for implementing videoconferencing services are distributed between an onboard processor located within the appliance and the central processing unit (CPU).of the PC. In particular, the onboard processor handles compression of a locally generated audio stream (typically representative of the speech of the local user), compression of a locally generated video stream (typically representative of an image of the local user), and echo cancellation and decompression of at least one remotely generated audio stream (typically representative of the speech of a remote user).
The compressed local audio and video streams, and the decompressed and echo cancelled remote audio stream, are conveyed to the PC through the USB interface. The compressed local audio and video streams are directed to a network interface for transmission over a network to a remote conference endpoint. The PC also receives compressed remote audio and video streams. The PC is configured to handle decompression of the compressed remote and local video streams, display of the local and remote video streams, and (optionally) playing of the audio stream. The PC additionally handles execution of a user interface, packetization of media streams, call establishment and control operations, and low-level network connectivity tasks.
In preferred embodiments, the videoconferencing appliance and PC perform audio and video compression/decompression and media stream packetization, and call establishment/control operations in accordance with the requirements set forth in the ITU H.323 Recommendation. By utilizing the H.323 protocols, the personal videoconferencing system may intercommunicate with any other H.323-compliant conference endpoints, as well as with (via a gateway) with H.320- and H.321-compliant endpoints.
Use of the distributed processing architecture advantageously enables high quality videoconferencing services to be achieved on a PC or similar platform. Further, by compressing local audio and video streams at the videoconferencing appliance, high quality audio and video may be sent over a standard USB connection without exceeding the connection""s bandwidth.